Detailed observations from the Spitzer and WISE space telescopes and the Very Large Telescope in Chile show that WR 102ka, one of the most massive stars in the Milky Way, is not associated with any nearby cluster of stars. The evidence counters the theory that all stars form in clusters, a team of astronomers argues in a paper that appeared October 22 on arXiv.org.

WR 102ka, which sits 26,000 light-years from Earth in the direction of the constellation Sagittarius, is about 100 times as massive as the sun and is not far from the center of the Milky Way. Since the center of the galaxy is very hot, dense and close to a supermassive black hole, the details of star formation may be different from other places in the galaxy. The environment could explain how WR 102ka and other giant stars in the region may have formed all alone, the astronomers argue.

Their paper has been accepted for publication in the Monthly Notices of the Royal Astronomical Society.